二次曲线拟合算法的统计性能分析与改进

传统的二次曲线拟合使用标准特征值分析算法。通过统计分析技术 ,可知该技术在拟合数字二次曲线时 ,存在估计偏差大、均方误差大的缺点。其产生原因是数据噪声的有色性和自相关函数矩阵的条件数过大 ,因此白化数据噪声和正则化变换是提高曲线拟合的有效措施。这从理论上有力地支持了Hartley提出的正则化算法。通过理论分析和计算机仿真实验 ,表明了降维EVD技术固有地同时具备噪声预白化功能和数据正则化功能 ,因此它能给出均方误差相当小的无偏估计。由于它无须进行预白化变换或正则化变换 ,并把最优化过程的维数从 6降为 2 ,所以它还具有计算快速、实现简单方便的优点。     

体育科研三维方法述要(上)

将常规的体育科研方法区分为三个相互关联的维度，其中，取材维含括观察、实验、假设三层阶，分别强调思考、目标、理论的不可或缺性；程序维依循一般思辨、专一选题、采集素材、整理素材、推理判断，验察修正六环节；课题维则从生物性学科和社会性学科两大方面寻求变革。最后还论及撰写文章十要点和缩减文字三要诀。     

国外常用实时软件系统比较

比较分析了国外9种实时软件系统的功能,包括交流功能、特有功能、用户界面、咨 询员界面、系统及培训信息等。     

Proximal advantage in knowledge diffusion: The time dimension

This paper intends to explore the impact of geographic proximity on the diffusion of knowledge in the form of publication citations, and argues that codified knowledge is transmitted faster in proximity and is subject to similar geographic constraints as tacit knowledge. The geographic proximity advantage would be particularly relevant in the early stage of dissemination. We collected three sets of research articles published in 1990, 2000 and 2010 and compared the longitudinal citations they received domestically and from abroad. The study found that domestic citations accumulate faster and reach their peak much earlier than foreign citations, and the difference is most evident in the first few years after publication. The result shows that geographic proximity does play a role in the speed of knowledge diffusion and points to the network effect for citations. Those located closer to the knowledge origin would be exposed and react to publications faster due to the additional opportunities of research exchange and network.     

College course scarcity and time to degree

College students are taking longer to earn baccalaureate degrees now than ever before, but little is known about institutional factors that may contribute to this trend. In this paper we investigate an important institutional constraint—course scarcity—that we hypothesize may be associated with increased time to degree. We employ a unique administrative dataset from a large, moderately selective, public institution and use an instrumental variables approach, identifying off the random registration times assigned to students. Results suggest that course scarcity does not delay students’ graduation. We explore alternative explanations for our findings and discuss a variety of other factors correlated with time to baccalaureate completion.     

Global dimension of weak smash product

INTRODUCTION In (Auslander, 1995), the author established the relationship of homological dimension between skew group algebra ΛG and Λ. Recall from Corollary 4.7 and Corollary 4.10 in (Auslander, 1995) that gl.dim(ΛG)=gl.dim(Λ) where ΛG is a skew group algebra with the order of G invertible in Λ. Recently, more and more mathematicians have studied homological dimension for Hopf algebra. Yang (2002) gave the relationship of homological dimension between smash product algebra A#H…     

新时代高校辅导员工作理念转变的三个维度

中国特色社会主义进入新时代为高校思想政治工作带来了新的起点,面对党和国家对思想政治工作的新要求,面对大学生成长发展的新期待,高校辅导员要从三个维度转变工作理念:从灌输走向对话,努力做大学生政治思想的积极引导者;从管理走向服务,努力做大学生成长成才的科学指导者;从经验走向研究,努力做大学生思想政治教育的潜心研究者。     

从战时共产主义向新经济政策的转变看列宁的与时俱进

列宁亲自制订的战时共产主义政策与新经济政策内容截然不同，却均抓住了各自面临的主要矛盾，拯救了新生的苏维埃政权。剖析其问之实事求是态度及与时俱进精神，了解其中对经典社会主义理论之突破与发展，对把握列宁主义精髓大有裨益。     

用幻方引进向量空间—德国数学建模实例

用幻方作为一种具体的向量模型，直观引入向量空间的基本概念，反过来又用高观点指导幻方结构的研究。